Making cars more fuel efficient

Making cars more fuel efficient
fuel effi    12/04/05   20:13   Page 1




        Technology for Real Improvements on the Road

        Studies show that cars use significantly more fuel per kilometre than                                                                             EUROPEAN CONFERENCE OF MINISTERS OF TRANSPORT
        suggested by official certification test ratings. While the exact size
        of this gap is poorly understood there is speculation that the gap
        is growing as a percentage of the tested value. This has raised                                                                                        I N T E R N AT I O N A L E N E R G Y AG E N C Y




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        concerns that national fuel efficiency and CO2 emissions reduction




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        of technologies are identified that, together, could
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            -:HSTCSC=VUXYXW:             (75 2005 06 1 P) ISBN 92-821-0343-9
Making cars more fuel efficient
Fuel effi p1GB   14/04/05   15:08   Page 1




                                             EUROPEAN CONFERENCE OF MINISTERS OF TRANSPORT



                                                  I N T E R N AT I O N A L E N E R G Y AG E N C Y




          making cars more fuel efficient
                       Technology for
                   Real Improvements
                          on the Road
page2-20x27-IEA   14/03/05   9:54   Page 1




                                           I N T E R N AT I O N A L E N E R GY AG E N C Y


                   The International Energy Agency (IEA) is an autonomous body which was established in
                   November 1974 within the framework of the Organisation for Economic Co-operation and
                   Development (OECD) to implement an international energy programme.

                   It carries out a comprehensive programme of energy co-operation among twenty-six of the
                   OECD’s thirty member countries. The basic aims of the IEA are:

                   • to maintain and improve systems for coping with oil supply disruptions;

                   • to promote rational energy policies in a global context through co-operative relations with
                     non-member countries, industry and international organisations;

                   • to operate a permanent information system on the international oil market;

                   • to improve the world’s energy supply and demand structure by developing alternative
                     energy sources and increasing the efficiency of energy use;

                   • to assist in the integration of environmental and energy policies.

                   The IEA member countries are: Australia, Austria, Belgium, Canada, the Czech Republic,
                   Denmark, Finland, France, Germany, Greece, Hungary, Ireland, Italy, Japan, the Republic of
                   Korea, Luxembourg, the Netherlands, New Zealand, Norway, Portugal, Spain, Sweden,
                   Switzerland, Turkey, the United Kingdom, the United States. The European Commission takes
                   part in the work of the IEA.




                                                       © OECD/IEA, 2005

                        No reproduction, copy, transmission or translation of this publication may be made
                                   without written permission. Applications should be sent to:

                               International Energy Agency (IEA), Head of Publications Service,
                                    9 rue de la Fédération, 75739 Paris Cedex 15, France.
Cover_A.fm Page 1 Wednesday, April 6, 2005 4:38 PM




                    EUROPEAN CONFERENCE OF MINISTERS OF TRANSPORT (ECMT)


              The European Conference of Ministers of Transport (ECMT) is an inter-governmental organisation
          established by a Protocol signed in Brussels on 17 October 1953. It comprises the Ministers of
          Transport of 43 full Member countries: Albania, Armenia, Austria, Azerbaijan, Belarus, Belgium,
          Bosnia-Herzegovina, Bulgaria, Croatia, the Czech Republic, Denmark, Estonia, Finland, France,
          FRY Macedonia, Georgia, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Liechtenstein, Lithuania,
          Luxembourg, Malta, Moldova, Netherlands, Norway, Poland, Portugal, Romania, Russia, Serbia and
          Montenegro, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey, Ukraine and the United Kingdom.
          There are seven Associate member countries (Australia, Canada, Japan, Korea, Mexico, New Zealand and the
          United States) and one Observer country (Morocco).
               The ECMT is a forum in which Ministers responsible for transport, and more specifically the inland
          transport sector, can co-operate on policy. Within this forum, Ministers can openly discuss current
          problems and agree upon joint approaches aimed at improving the utilization and at ensuring the
          rational development of European transport systems of international importance.
              At present, ECMT has a dual role. On one hand it helps to create an integrated transport system
          throughout the enlarged Europe that is economically efficient and meets environmental and safety
          standards. In order to achieve this, it is important for ECMT to help build a bridge between the European
          Union and the rest of the European continent at a political level.
               On the other hand, ECMT's mission is also to develop reflections on long-term trends in the
          transport sector and to study the implications for the sector of increased globalisation. The activities in
          this regard have recently been reinforced by the setting up of a New Joint OECD/ECMT Transport
          Research Centre.




                                 Further information about the ECMT is available on Internet at the following address:
                                                                 www.oecd.org/cem
                                  © ECMT 2005 – ECMT Publications are distributed by: OECD Publications Service,
                                             2, rue André Pascal, 75775 PARIS CEDEX 16, France
FOREWORD AND ACKNOWLEDGEMENTS -   5




                              FOREWORD AND ACKNOWLEDGEMENTS



     This report provides a technical analysis of why vehicles perform better in fuel economy test
procedures than they do in actual operation on the road. It examines how the gap between test and
“on-road” emissions can be closed. A variety of technologies are examined that, whilst they show now
gains in the tests used to certify vehicles for sale, could improve fuel economy and reduce CO2
emissions in the real world. Manufacturers have little or no incentive to introduce these technologies
although they could be used to cut emissions by over 10%. The practical information presented here
should assist policy makers in identifying technologies and other strategies such as driver training to
promote fuel efficiency on the roads and provide incentives for the uptake of the relevant technologies.

     This book was produced jointly by the European Conference of Ministers of Transport and the
International Energy Agency, Office of Energy Technology and R&D. The ECMT and IEA would like
to thank Mr. K. G. Duleep of EEA, Arlington, Virginia for providing the main analysis underlying this
report. We would also like to thank Novem, the Dutch energy agency for important contributions in
the area of efficient driving behaviour. Useful comments were received from many individuals,
including Tom Howes (European Commission, DG-TREN), Dan Santini (Argonne National
Laboratory, US), and Feng An (independent consultant). Of course any errors or omissions remain the
responsibility of ECMT and IEA.




TECHNOLOGY AND POLICIES TO IMPROVE VEHICLE IN-USE FUEL ECONOMY – ISBN 92-821-0343-9 - © ECMT, 2005
TABLE OF CONTENTS            -7




                                                        TABLE OF CONTENTS



EXECUTIVE SUMMARY .................................................................................................................... 9
   Literature Review.............................................................................................................................. 10
   Technologies to Reduce Shortfall ..................................................................................................... 11
   Technology Cost-effectiveness ......................................................................................................... 12
   Policies to Promote Technology Introduction................................................................................... 18

1. INTRODUCTION ........................................................................................................................... 21

2. LITERATURE REVIEW OF “SHORTFALL” .............................................................................. 23
   Mix of Driving Environments........................................................................................................... 24
   Road Conditions/Topography ........................................................................................................... 24
   Vehicle Accessories and Cargo......................................................................................................... 25
   Vehicle Technology-Specific Effects ............................................................................................... 25

3. THE EFFECT OF AMBIENT CONDITIONS, VEHICLE MAINTENANCE
AND DRIVER BEHAVIOUR ON FUEL ECONOMY ...................................................................... 31
   The Effect of Ambient Conditions on Fuel Economy....................................................................... 31
   The Influence of Vehicle Maintenance on Fuel Economy................................................................ 31
   The Importance of Driver Behaviour for Fuel Economy.................................................................. 33

4. DRIVING CYCLES AND SHORTFALL DATA .......................................................................... 37

5. TECHNOLOGIES TO IMPROVE FUEL ECONOMY OF GASOLINE VEHICLES .................. 29
   Engine Technologies......................................................................................................................... 45
   Transmission Technologies............................................................................................................... 46
   Accessory Technologies ................................................................................................................... 47
   Hybrid Technologies......................................................................................................................... 48
   Tyre Technology ............................................................................................................................... 49
   Tyre Inflation .................................................................................................................................... 51
   Fuel-efficient Lubricants................................................................................................................... 53
   Fuel Economy Gains from Oils ........................................................................................................ 39
   Headlights and Daytime Running Lights.......................................................................................... 40
   Fuel-saving Driver Support Devices................................................................................................. 57




TECHNOLOGY AND POLICIES TO IMPROVE VEHICLE IN-USE FUEL ECONOMY – ISBN 92-821-0343-9 - © ECMT, 2005
8 - TABLE OF CONTENTS


6. IMPROVING THE FUEL ECONOMY OF DIESEL VEHICLES................................................. 63
   The Benefits of Diesel....................................................................................................................... 63
   New Engine Performance ................................................................................................................. 64
   Diesel Vehicle Shortfall .................................................................................................................... 65
   Low Ambient Temperatures ............................................................................................................. 65
   Aggressive Driving ........................................................................................................................... 66
   Traffic Conditions ............................................................................................................................. 66
   Effects of Other Technologies .......................................................................................................... 68

7. TECHNOLOGY COSTS AND POLICIES TO PROMOTE TECHNOLOGIES
THAT IMPROVE FUEL ECONOMY ................................................................................................ 69
   Technology by Location Class.......................................................................................................... 70
   Technology Payback Period and Cost per Tonne CO2 Reduction .................................................... 71
   Policies to Promote Technology Introduction................................................................................... 78

REFERENCES ..................................................................................................................................... 81




                           TECHNOLOGY AND POLICIES TO IMPROVE VEHICLE IN-USE FUEL ECONOMY – ISBN 92-821-0343-9 - © ECMT, 2005
EXECUTIVE SUMMARY   -9




                                           EXECUTIVE SUMMARY



      There is a gap between light-duty vehicle fuel economy as measured on official certification tests
in OECD countries and actual on-road fuel economy1. The existence of this gap, or shortfall, is widely
known and some countries already adjust test fuel economy values by a correction factor to account
for it. In recent years, there has been speculation that the gap is growing as a percentage of the
certified, tested value. This has raised concerns that national fuel consumption reduction goals based
on test values will not be met in reality and that consumers will lose faith in reported fuel economy
figures. This report analyses available data on the gap and examines technologies available to reduce it
along with policies to promote their adoption. This information can be used to select technologies and
measures for reducing oil use and CO2 emissions that deliver fuel economy improvements on the road
in spite of any deficiencies in the test cycles used to measure it.

      An extensive review of the literature reveals that there have been few recent assessments of
shortfall in OECD countries. New empirical studies are needed and would be very valuable. These
could be conducted, for example, by having a sample of drivers keep logs of vehicle travel and actual
fuel consumption, in different areas and for different types of vehicles, and then comparing this data to
test-rated fuel economy figures.

     An engineering analysis of available technologies has identified several that have little or no
impact on fuel economy test results but are potentially useful for improving actual on-road fuel
economy. Some (though not all) of these are estimated to be cost-effective for reducing fuel
consumption from the consumer’s viewpoint, based on a payback period2 of three years. More of the
technologies, in more situations, are estimated to provide net benefits to society – i.e. their costs are
more than offset by the private plus the social benefits derived (associated with fuel savings and
reduced oil dependency) – and they provide relatively low cost CO2 emissions reductions.

     The most cost-effective technologies are related to reducing the fuel economy shortfall for
gasoline vehicles in cold ambient temperature and dense traffic conditions. These technologies are
electric water pumps, energy efficient alternators, heat batteries (for pre-warming engine oil on start
up) and 5W-20 oil. Under cold ambient, dense traffic conditions, the combination of all these
technologies could increase fuel economy by around 10% on average and up to 20% during the winter.
These benefits are available to urban drivers in areas such as Northern Europe, Canada, the Northern
U.S. and Northern Japan. This is a promising area for policy intervention.

     These and other technologies are sometimes cost effective in other situations (such as warmer
climates or highway driving conditions) depending on fuel prices and average annual distances driven.
A number of technologies were found not to be cost-effective in any of the conditions considered.




TECHNOLOGY AND POLICIES TO IMPROVE VEHICLE IN-USE FUEL ECONOMY – ISBN 92-821-0343-9 - © ECMT, 2005
10 - EXECUTIVE SUMMARY


     In addition to technologies, one non-technology measure was also considered: driver training
programmes. With careful programme design, driver training can provide significant fuel savings and
appears cost-effective in all driving conditions. A key assumption is that drivers continue to follow the
recommended driving styles after the period of training. Several technologies are available to
encourage fuel-efficient driving (such as shift indicator lights and fuel-use indicators) and are already
provided in many cars. When incorporated in new vehicle designs they can be added to cars at very
low cost (less than 10 or Dollars / 10 Euros).

Literature Review

      Very detailed studies of shortfall completed in the early 1980s continue to be the only
comprehensive sources of data to date. A small number of limited studies on shortfall have been
conducted since then but the only significant source of data on in-use fuel economy is from a survey in
Canada. The findings do not suggest that shortfall has increased dramatically in the last 20 years, or
that the causes of shortfall identified earlier have changed markedly. In that period, only the EU has
changed its test procedure, by adding the ‘extra urban’ cycle, and this has probably not significantly
affected the level of shortfall.

     The findings of the most comprehensive studies on shortfall in the early 1980s showed that:

     •   Shortfall increases as a percentage with increasing absolute fuel economy (measured in MPG
         or km/l).

     •   Light trucks have higher shortfall levels than cars.

     •   Shortfall is also a function of vehicle drive-train technology and possibly manufacturer
         specific calibrations.

      The 1995 Canadian survey of on-road fuel economy showed results largely consistent with the
findings from the 1980s in both magnitude and trend. Researchers have speculated that shortfall may
be increasing either due to worsening traffic condition and higher highways speeds, or due to changes
in vehicle technology (direct injection engines, hybrid technologies). This may be true but remains
unproven with real world data. Road test data by magazines and TV programs do show manufacturer
and technology specific shortfall differences, but the small sample of vehicles and unrepresentative
test conditions do not permit any significant conclusions to be drawn.

     Recent programs promoting driving-style improvement through training and technology aids
show that improvements in fuel consumption of around 10% are possible from training, although
drivers generally require feedback instrumentation to maintain performance. (The driver training effect
assumes the maintenance of more constant speeds but does not assume a speed reduction.) The
significant contribution of driving styles to shortfall was recognized even in the studies conducted
20 years ago, and similar margins of improvement were thought possible then.




                   TECHNOLOGY AND POLICIES TO IMPROVE VEHICLE IN-USE FUEL ECONOMY – ISBN 92-821-0343-9 - © ECMT, 2005
EXECUTIVE SUMMARY   - 11



Technologies to Reduce Shortfall

      A wide variety of fuel-economy technologies have been adopted by vehicle manufacturers since
the 1980s but a majority of them have little or no effect on shortfall. Some technologies, notably
electronic engine management systems, can increase shortfall by tailoring engine operation to the test
cycle. Other technologies, such as diesel engines and, possibly, gasoline direct injection engines, could
reduce shortfall under many operating conditions. Small diesel-engine-powered vehicles typically
have much lower shortfall than gasoline-powered vehicles because a diesel engine requires less cold
start and acceleration fuel enrichment and uses much less fuel when the vehicle rests “at idle”.
Therefore, while the technologies listed below are also applicable to diesel powered vehicles,
technologies related to cold-starts and idling offer much larger benefits for gasoline engines.

     A number of technologies aimed at improving gasoline vehicle fuel economy in off-test-cycle
conditions (i.e. travel situations that are different from those characterized during test-cycle
measurement) have been developed but have generally not penetrated the market. These technologies
include:

     •     Electrically driven oil and water pumps.

     •     Efficient alternators.

     •     Efficient air conditioners and heat pumps.

     •     Fast engine warm-up technologies.

     •     Aids to improve driving habits.

     •     Idle-off systems.

     •     42V electrical systems.

     •     Adaptive cruise control.

      The reason that such technologies are not included in most vehicles is wholly or partly due to
their limited benefit on the fuel economy test cycle.

     In addition to these technologies, tyres and lubrication engine oil can impact on-road fuel
economy and reduce shortfall. These are replaced periodically over a vehicle’s life and the
replacement market is not well optimized for fuel economy. Tyre “rolling resistance” varies
considerably by tyre model and the best tyres can reduce fuel consumption by several percent
compared to average types. Yet no tyre rolling resistance information is available to consumers in
most OECD countries. Increased monitoring of tyre pressure could also yield some fuel savings; it
should be possible to adapt tyre safety-related pressure monitoring systems to provide information on
moderate under-inflation as well, with low-inflation indication provided to drivers via a dashboard
signal. Data on the average type of oil actually used in the replacement market is limited, but small



TECHNOLOGY AND POLICIES TO IMPROVE VEHICLE IN-USE FUEL ECONOMY – ISBN 92-821-0343-9 - © ECMT, 2005
12 - EXECUTIVE SUMMARY


benefits in fuel economy might be realized if the market for fuel efficient replacement oil were to be
optimized.

     Engine-related maintenance actions (in contrast to other maintenance actions such as tyre
pressure monitoring and replacement tyre and oil choice), do not now have much impact on shortfall.
This is because engines are designed to need maintenance less often than they used to, because
electronic engine controls have made tampering and maladjustment difficult, and because emission
inspections in most OECD countries provide strong incentive for yearly or biennial vehicle
maintenance.

     One emerging problem is the replacement of standard electronic engine management system
components with customised control chips, designed to maximise performance in terms of power
output in on-road conditions regardless of the effect on exhaust emissions and fuel consumption. This
was not examined in this report but anecdotal evidence suggests it may be a growing contributor to
shortfall.

      Aggressive driving continues to be a major factor contributing to shortfall. A number of
technological aids to assist the driver to drive in a more fuel-efficient manner are available. The
literature review shows that real world gains of 5 to 10% in fuel economy are possible, on average,
from the impacts of these technologies (combined with driver training) on improved driving habits.

Technology Fuel Economy Impacts and Cost-effectiveness

     The literature review and engineering analysis presented in this report document a number of
technologies available to reduce shortfall. The term “available” is used to indicate that no technical
barrier exists for commercialization, but the technology has seen only limited or no introduction yet in
the market. This is partly because auto-manufacturers will be able to claim little or no fuel economy
benefit on the official certification test and partly because ambient and geographic conditions vary
greatly among OECD countries from region to region and even within countries. Since the benefits of
technologies in terms of reducing shortfall are often significant only under specific ambient/traffic
conditions, manufacturers are unwilling to standardize these technologies across an entire model line.
It may not be possible to find a “one size fits all” solution to the issue of technology under-utilization.
Technologies most useful to Sweden or Canada sometimes have limited value to consumers in
southern France or the southern States of the U.S. Similarly the ranking of technologies by cost-
effectiveness varies with local conditions.

      There are two types of important distinctions in terms of ambient conditions affecting shortfall:
temperature (cold or hot) and traffic (dense or light, typically corresponding to large city or small
city/rural conditions). The distinctions are somewhat subjective, but for this analysis the following
characteristics were assumed for each situation:

     •    Locations with cold ambient temperatures - where daily low ambient temperatures are below
          10°C for over six months.




                   TECHNOLOGY AND POLICIES TO IMPROVE VEHICLE IN-USE FUEL ECONOMY – ISBN 92-821-0343-9 - © ECMT, 2005
EXECUTIVE SUMMARY   - 13



     •     Location with hot ambient temperatures - where daily high temperatures exceed 25°C for
           over six months.

     •     Dense traffic, with city-wide average speeds below 25 km/hr (16 mph).

     •     Light traffic, with city-wide or rural average speeds in excess of 40 km/hr (25 mph),
           corresponding to freely flowing traffic.

     When the two ambient conditions are combined with the two traffic conditions, they create four
driving situations. Although some technologies have benefits that fall across all four of these
quadrants, most technologies perform well only for one or two.

     Thirteen technology options to reduce shortfall for gasoline vehicles were examined. The
technology cost, or more accurately the retail price equivalent, (an estimate of how much the retail
price for vehicles would increase under competitive conditions if the technology were added to the
vehicles) was estimated for each option.

      Technology fuel economy benefits were estimated using limited test data available in the
literature and drawing on well-understood engineering relationships. Assumptions behind each
estimate are described in the following chapters. Results are shown in Figure E-1, which shows that
the potential benefits per technology are generally small, in the range of 1 to 5%, with only three
exceptions: for idle stop/start in dense traffic; driver training in light traffic; and adaptive cruise
control in light traffic conditions3. As would be expected, certain technologies provided a benefit only
under certain conditions; for example efficient air conditioners in hot ambient conditions and idle
stop/start under dense (i.e. stop/start traffic) conditions.

     Given the different effects of technologies in different situations, the overall benefit to each
driver depends on the share of driving done in each situation. To estimate average effects across all
drivers in a country, the aggregate driving shares in each situation should be estimated. It should also
be noted that technology benefits are not necessarily additive; for example, adaptive cruise control
performs a function similar to driver training and applying both will result in less benefit than the sum
of their individual effects. Combined effects have not been estimated in this study, except a general
estimate that application of all, or even most, of these technologies should combine to reduce fuel use
by 10% or more.

     For diesel vehicles, the fuel savings achievable were found to be generally similar or slightly
lower than those for gasoline vehicles. The biggest differences concern electric water pumps and idle
stop/start. These are only about half as effective for diesels as for gasoline vehicles. On the other hand,
adaptive cruise control impacts on diesels are 50% bigger – with an estimated 15% reduction in fuel
use per kilometre, compared to 10% for gasoline vehicles.

     One measure of technology cost-effectiveness is the time required to pay for the technology from
the fuel savings. This metric relates to consumers’ willingness to pay for this technology (and
therefore manufacturer’s willingness to put technologies into the vehicles they sell). The pay-back
period is a function of local fuel prices, annual driving distances and baseline vehicle fuel economy.




TECHNOLOGY AND POLICIES TO IMPROVE VEHICLE IN-USE FUEL ECONOMY – ISBN 92-821-0343-9 - © ECMT, 2005
14 - EXECUTIVE SUMMARY


Three cases are considered as examples of the range of these variables encountered among OECD
countries. These cases are:

      •        US gasoline vehicle: fuel cost of $1.50 per gallon (Euro 0.32 per litre), with a baseline fuel
               economy of 27 mpg (8.7 l/100 km), driven 12 000 miles (19 200 km) annually.

      •        EU gasoline vehicle: fuel cost of Euro 0.90 per litre ($4.25 per gallon), with a baseline fuel
               economy of 7.5 l/100 km (31.4 mpg), driven 15 000 km (9 300 miles) annually.

      •        EU diesel vehicle: fuel cost of Euro 0.75 per litre ($3.55 per gallon) with a baseline fuel
               economy of 5.6 l/100 km (42.0 MPG), driven 18 000 km (11,200 miles) annually.



                Figure E-1. Estimated Fuel Savings (Percent) under Different Ambient Conditions
                                           for Gasoline Vehicles

             12%

             10%

             8%

             6%

             4%

             2%

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                              Dense Traffic, Cold   Light Traffic, Cold   Dense Traffic, Hot   Light Traffic, Hot




Source: Analysis presented in Chapters 5-7.


     A second measure, of “social” cost and benefit, was also calculated for each technology in each
situation, using CO2 emissions reduction cost-per-tonne as the metric. This was calculated using an
estimate for untaxed fuel cost ($0.40 per litre) and discounting fuel use over average vehicle life at a
social discount rate of 3% per year. The results of the analysis on a payback-period and CO2-cost basis
are summarised below, and presented in more detail in the final chapter of the report.




                        TECHNOLOGY AND POLICIES TO IMPROVE VEHICLE IN-USE FUEL ECONOMY – ISBN 92-821-0343-9 - © ECMT, 2005
EXECUTIVE SUMMARY   - 15



     Under the assumptions of a gasoline vehicle in Europe, with a regime of European fuel prices,
fuel economy and average driving levels, several gasoline engine technologies are cost-effective from
the consumers’ viewpoint, especially at cold temperatures. This is illustrated in Figure E-2 in the form
of payback times shown for cold and hot ambient conditions (and assuming a 50/50 share of driving in
light and heavy traffic conditions). Under cold ambient conditions in the EU, most technologies,
except for idle stop and adaptive cruise control, are paid for by fuel savings in three years or less, and
should therefore be attractive to many consumers. Under hot ambient conditions, the situation is less
favourable to most technologies. This is to be expected since the test procedure represents hot ambient
conditions well, and cost effective technologies are likely to be already introduced as a result of
market pressure. Under assumptions of a gasoline vehicle in the US, the situation is less favourable,
mainly since taxed fuel prices are much lower than in the EU. The low prices are partly offset by
higher fuel use, but only partly.



                                             Figure E-2. Technology Payback Period (Years), Gasoline Vehicles

                                      14


                                      11
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Source: Analysis presented in Chapters 5-7.


      Results on the basis of net cost-per-tonne of CO2 reduction are presented in Figure E-3. Instead of
average taxed fuel prices, which are the relevant figures for evaluating consumer pay-back times, the
estimates in Figure E-3 are based on resource costs: i.e. an untaxed retail fuel cost of $0.40 (reflecting
about $36/bbl oil price, plus refining, transport and retailing costs). Fuel use during the first 10 years
of vehicle life is included, at 3% per year social discount rate. No external or social costs are added to
this price, in part to keep the cost-effectiveness estimates conservative (adding external costs related to



TECHNOLOGY AND POLICIES TO IMPROVE VEHICLE IN-USE FUEL ECONOMY – ISBN 92-821-0343-9 - © ECMT, 2005
16 - EXECUTIVE SUMMARY


oil use and dependency would raise the value of fuel saving and lower CO2 reduction costs).
Never-the-less, the results tend much more towards cost-effectiveness than they do from the consumer
pay-back approach. Most technologies are cost effective (have a low or negative cost per tonne CO2
reduction) in at least one of the geographic/ambient circumstances considered. Nearly all of the
technologies reduce CO2 emissions for under $100 per tonne in at least some situations, which
although high in relation to the cost of some CO2 reduction strategies in other sectors, is fairly
competitive with other options for reducing CO2 emissions in the transport sector. Most of the
technologies reduce CO2 for less than zero cost in at least some situations (i.e. the value of fuel
savings to society is greater than the cost of technology). These are clearly “no-regrets” technologies
from a societal point of view. Results are somewhat better for US conditions than for Europe, since in
this case the same fuel cost is assumed for both regions while US fuel use per vehicle per year, and
thus the potential fuel savings, remains significantly higher than in Europe.


                                                     Figure E-3. CO2 Reduction Costs ($/tonne), Gasoline Vehicles

                                $1,200

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       dollars per tonne CO2




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Source: Analysis presented in Chapters 5-7.


     The literature review, mainly from U.S. studies, suggests that driver training often is not terribly
cost effective. However, the Netherlands has successfully exploited driving simulators for training at
much lower cost than estimated in the North American examples – extending the conditions in which
appropriate driver training shows good returns. The Netherlands’ estimates are used here, showing that
driver training has short payback times and near-zero cost per tonne for CO2 reduction.



                                                   TECHNOLOGY AND POLICIES TO IMPROVE VEHICLE IN-USE FUEL ECONOMY – ISBN 92-821-0343-9 - © ECMT, 2005
EXECUTIVE SUMMARY   - 17



     The diesel case is less conducive to technology introduction partly because of lower fuel cost
savings and partly because diesel engines use less fuel during cold start. However, shift indicator
lights are cost effective for diesels in all ambient and driving conditions, and driver training and tyre
pressure indicators appear to be at the margin of cost-effectiveness for the consumer. Under U.S.
vehicle and fuel price assumptions, only a few cold-start related technologies are cost effective to
consumers in cold ambient conditions. Adaptive cruise control is far from cost-effective under all
scenarios, and will only be marketed for reasons other than fuel economy. From a CO2 reduction cost
point of view, most technologies are found to be almost as cost effective as they are for gasoline
vehicles.

      The cost-effectiveness analysis provides a good illustration of why most of the 13 technologies
identified have not made much headway in the market. Even at fuel prices prevalent in the EU, most
technologies are not very cost–effective for consumers (payback times exceed three years), or are cost-
effective only under the cold ambient/dense traffic conditions case. The notable exceptions are the
shift indicator light (SIL) and the dual cooling circuit system together with driver training (following
the European rather than North American approach). The SIL, applicable to manual transmissions, has
already penetrated the U.S. market but has not penetrated the EU, possibly due to the fact that
manufacturers do not get any fuel economy credit for its adoption on the test procedure. The dual
cooling circuit requires an engine cooling system redesign, and is likely to be introduced slowly as
gasoline engines are updated or redesigned. The costs of this technology are primarily associated with
capital investment in redesign, and best accomplished at the beginning of a product cycle for each
engine model.

     In contrast to modest cost-effectiveness of gasoline technologies for consumers, most of the
technologies appear to be quite cost effective from a CO2 reduction point of view, suggesting that
government intervention is merited to bring these technologies into the market and achieve the
potential social benefits they offer.

     A number of gasoline vehicle technologies are cost-effective from both consumer and societal
viewpoints, and are primarily associated with shortfall reduction in cold ambient temperature and
dense traffic conditions. These technologies include the electric water pump, energy efficient
alternator, heat battery (for pre-warming engine oil on start up), dual cooling circuits and 5W-20 oil.
Under cold ambient dense traffic conditions, the combination of all these technologies could increase
fuel economy by over 10%, on average, or up to 20% during winter months. These benefits are
available to most urban locations in Northern Europe, Canada, the Northern U.S. and Northern Japan.
This is a promising area for policy intervention.

     For diesel vehicles, methods to discourage high speed driving and discourage shifting gears at
high RPM appear to be the most cost-effective areas for intervention. However, perhaps due to the
inherently lower shortfall observed for diesel vehicles in the early literature, there has not been much
focus on examining the impact of on-road conditions on diesel vehicle shortfall. More research on
diesel shortfall is warranted given the current rapid dieselisation of European passenger car fleets, and
indications from the small number of more recent tests in Europe that shortfall in modern diesels may
be much larger than for older diesel technology.




TECHNOLOGY AND POLICIES TO IMPROVE VEHICLE IN-USE FUEL ECONOMY – ISBN 92-821-0343-9 - © ECMT, 2005
18 - EXECUTIVE SUMMARY


Policies to Promote Technology Introduction

      A clear message from the available information on shortfall is that current test procedures in both
the US and EU do not accurately measure average on-road fuel economy of light-duty vehicles.
On-going efforts to better understand real world driving cycles and adopting these in revised test
procedures would help to minimize this inaccuracy. Governments have shown a reluctance to revise
test procedures, perhaps due to the complex and controversial nature of establishing them. The EU did
revise their fuel-economy test procedures in the 1990s, and the US does provide an adjusted fuel
economy figure on labels shown on car windows at dealerships, that reflects an assumption of lower
on-road than test MPG performance. But these steps appear insufficient to encourage manufacturers to
widely adopt the technologies covered in this report.

    Short of revising fuel economy test procedures, a number of other policies may prove useful to
encourage wide-spread adoption of these technologies, particularly the more cost-effective ones.

     Providing information to consumers on the benefits of technologies in different situations
(particularly cold temperatures and heavy traffic conditions) would be a positive step but may provide
only limited motivation for their adoption. As noted, the net effect of any one technology is only a few
percent reduction in fuel consumption, and the cost-effectiveness is often marginal (three to four years
payback) from the consumer’s viewpoint. However, many of the technologies are quite cost-effective
from a societal point of view; further, some technologies also have pollutant emission benefits at cold
temperatures and the full cost of these systems need not be allocated to fuel savings alone. Many
OECD countries have cold temperature emission limits that could be made more stringent to force
adoption of these technologies. Modest fiscal incentives to manufacturers in the range of Euro 100
($120) per vehicle to reduce fuel consumption under cold ambient/slow speed conditions could
promote their use, at least in some countries and regions.

      It may also be possible to utilize voluntary agreements with manufacturers to introduce cost-
effective technologies in specific locations. For example, home air conditioners are now required to
meet a certain minimum efficiency level in the U.S. A similar (but voluntary) agreement could be
reached on vehicle air conditioners. Similar agreements could be made regarding the uptake of other
efficient technologies.

      As discussed, driver training is cost-effective, assuming drivers do not lapse into old habits once
the training is over. The technology to support fuel-efficient driving is already available in many cars,
or can be added at very low cost (less than $10). Government subsidized training programs appear to
be a viable means to provide the required training. Such programs should be instituted along with
publicity about the programs, and subsequent popularization with fuel-efficient driving contests, etc.

      Finally, programs can be implemented that encourage consumers to purchase more efficient
after-market products such as replacement tyres and oils. Better information, rating systems and
labelling are an important step. But stronger measures such as differentiated tax/subsidy systems based
on product performance, might provide bigger responses and help achieve important social benefits.

    Overall, it appears that there is an opportunity to improve average vehicle on-road fuel economy
by 10-15% at low cost, but it will require government actions to achieve this. Governments are



                   TECHNOLOGY AND POLICIES TO IMPROVE VEHICLE IN-USE FUEL ECONOMY – ISBN 92-821-0343-9 - © ECMT, 2005
EXECUTIVE SUMMARY    - 19



encouraged to explore the various policy options available to them, and select a set of technologies to
target that provide strong social benefits in the particular context (predominantly cold or warm
climate, urban v. rural, fuel prices, average travel distances and baseline vehicle fuel economy levels).
Of course, there are “scale economies” to developing consistent incentives across markets, so adoption
of single policy systems at the US or EU level may help send the strongest signals to the market, and
avoid confusion.

     Finally, this report is the first in many years to seriously explore this topic, and a key finding is
that much more data and analysis is needed. Vehicle testing programs to estimate actual on-road fuel
economy, and how it various by various situations and vehicle types, would be extremely useful.
Further work to test the benefits of various technologies in reducing fuel economy shortfall, especially
for diesel vehicles and new vehicle types such as hybrids, is also much needed. A study that includes
systematic in-use testing of hybrid-electric vehicles would be particularly useful, especially as more
models come into the market over the next few years.




                                                      NOTES



1.   Various terms are used to refer to vehicle fuel consumption rates, such as “fuel economy”, “fuel efficiency”
     and even “fuel consumption”. Throughout this publication “fuel economy” is used. It is generally measured
     in litres per 100km. In some places in the text mile-per-gallon (MPG) equivalents are also provided.

2.   Payback period is defined as first cost of the technology divided by the value of annual fuel savings.

3.   The cost of adaptive cruise control was found to prevent it from being a cost effective option for saving
     fuel, and conventional cruise control available already in the market achieves similar savings at much
     lower cost. However, adaptive cruise control may also provide important safety benefits.




TECHNOLOGY AND POLICIES TO IMPROVE VEHICLE IN-USE FUEL ECONOMY – ISBN 92-821-0343-9 - © ECMT, 2005
INTRODUCTION   - 21




                                              1. INTRODUCTION



     All vehicle technologies have some effect on both test cycle and on-road fuel economy. For some
the percentage reduction in fuel consumption achieved on the road is quite similar to that recorded on
standard test cycle results. For others there can be significant differences. This difference is frequently
termed “shortfall”. While the test cycle has defined conditions, on-road conditions are highly variable.
Technology evaluations of shortfall must therefore focus on the specific on-road conditions that are
most responsible for shortfall.

     This report describes how technologies and other measures affect and can contribute directly to
reducing fuel consumption and investigates how they influence the measurement of fuel consumption
through their relations with the parameters of vehicle fuel economy test cycles. The measurement of
vehicle fuel economy is important and it appears that there has been a sizable gap between the official
test cycle emissions and actual on-road vehicle emissions for some years. This gap, or shortfall,
undermines the official measurement of CO2 emissions and the achievement of national fuel economy
targets as well as consumer faith in the reported fuel economy performance of vehicles. Knowledge of
the causes of shortfall can be used to improve the test cycles themselves or to correct the results of
existing cycles, to provide a more accurate value of emissions and so ensure that consumer
expectations and Government targets are met.

     Most importantly this knowledge can be used to select approaches to reducing CO2 emissions that
deliver fuel economy improvements on the road in spite of any deficiencies in the test cycle. From this
perspective the report investigates the range of new technologies available to vehicle manufacturers
and the policies available to governments to make significant improvements to vehicle fuel economy,
through both technical and non technical means. The analysis for the report was undertaken for the
International Energy Agency (IEA) and the European Conference of Ministers for Transport (ECMT)
by Energy and Environmental Analysis, Inc. with input also from the Dutch energy agency NOVEM.

     It should be noted that the report examines technologies for light-duty vehicles. Heavy-duty
vehicles are not included nor are technologies that improve system performance by making traffic
flow more smoothly. These issues, while important, are beyond the scope of this report. It should also
be noted that driver behaviour is only addressed in so far as it conditions the impact of the
technologies reviewed on fuel economy. Driver training, and instrumentation to provide feedback to
drivers on the effects of their driving style on fuel consumption, is a key avenue for reducing CO2
emissions and resolving test cycle shortfall issues in its own right.

     In carrying out the analysis presented here, the first task was to review previous studies on the
subject. Much of the existing body of work on shortfall was undertaken in the late-1970s and early-
1980s during the fuel crises. Since that time, there have been very few studies on shortfall, and none
are as comprehensive as those conducted 20 years ago. A review of these studies is presented in
Chapter 2. More recent studies do not contradict earlier results but the number of vehicles sampled in



TECHNOLOGY AND POLICIES TO IMPROVE VEHICLE IN-USE FUEL ECONOMY – ISBN 92-821-0343-9 - © ECMT, 2005
22 - INTRODUCTION


these studies is generally too small to draw definitive conclusions. However, they do provide further
insight into the causes and nature of shortfall.

     The second task was to examine new technology being introduced into vehicle fleets and use
engineering analysis to estimate trends in shortfall as a result of technological change. The third task
also deals with technology, identifying available technologies that could be introduced to reduce
shortfall. Both tasks are covered in Chapter 5 for gasoline engine powered vehicles and in Chapter 6
for diesel engine powered vehicles. The analysis builds on the findings of the literature review.

     The final task was to develop “cost curves” of technologies and actions to reduce shortfall, and to
identify policies to encourage the uptake of cost-effective technology. The results are presented in
Chapter 7.

     The study found that due to the substantial variability of ambient and traffic conditions, it was not
possible to develop a single “supply curve” for technology applications. Rather, sets of technologies
best suited to shortfall reduction in specific climatic and traffic conditions were identified, and policies
to promote their uptake are suggested.




                   TECHNOLOGY AND POLICIES TO IMPROVE VEHICLE IN-USE FUEL ECONOMY – ISBN 92-821-0343-9 - © ECMT, 2005
LITERATURE REVIEW OF “SHORTFALL”   - 23




                            2. LITERATURE REVIEW OF “SHORTFALL”



       As noted in the introduction, the major systematic studies of fuel economy shortfall between
official certification test fuel economy and on-road fuel economy were completed in the late 1970s
and early-1980s. The studies identified the causes of shortfall, and also estimated the magnitude of
shortfall from surveys of vehicle owners. It is widely known that vehicle owners can have fuel
economy significantly different from the official test value, but governments generally believe that test
values should not be so biased that the vast majority of drivers experience lower fuel economy than
the official value used for consumer information. Hence the U.S. publishes estimates of fuel economy
for consumers that are discounted from the measured test value; the city cycle value is discounted by
10% and the highway cycle value by 22%. These discounts have not been changed for the last two
decades; similar adjustments have been used in some other OECD countries, though not in Europe.
There has been no recent large scale study involving survey data to see if the adjustment factors are
still appropriate for modern vehicles.

    The detailed studies conducted in the early 1980s do, however, provide useful insights for
examining how new technologies and changes to vehicle designs affect shortfall. The discussion
below provides a framework for examining the effects of new technology on shortfall.

     The on-road fuel economy of a specific vehicle is sensitive not only to the vehicle technology but
also to the local geography, ambient conditions, driving technique and vehicle state of
maintenance/age. Hence, a given vehicle type can have significant differences in fuel economy
depending on its owner and location. These facts have been widely recognized, and most government
fuel economy programs have a disclaimer on the accuracy of the test fuel economy.

     The late-1970s and early-1980s were periods when considerable work was done by regulatory
agencies in Europe, North America and Australia to examine the issue of shortfall. Several reports
provided a compendium of available information on this topic, including one published by the OECD1
in December 1981 and another published by the U.S. EPA2 in Fall 1980. The two reports identified
very similar sets of causal factors, although the USEPA report provided more quantitative
characterization of the effect of each causal factor.

     Given that test fuel economy is measured under a specific set of ambient conditions and with
specific driving cycles, the main reasons for shortfall can be grouped as follows:

     •     Ambient conditions.

     •     Mix of driving cycles and trips.

     •     Road conditions and topography.



TECHNOLOGY AND POLICIES TO IMPROVE VEHICLE IN-USE FUEL ECONOMY – ISBN 92-821-0343-9 - © ECMT, 2005
24 - LITERATURE REVIEW OF “SHORTFALL”


     •   Vehicle state-of-maintenance.

     •   Driver behaviour.

     •   Vehicle accessories and cargo.

     These factors and their effects on fuel economy as characterized in the OECD and EPA reports
are summarized below.

Mix of Driving Environments

      The mix of driving environments refers to the mix of city, suburban and highway driving (as
distinct from the cycle aggressiveness, which seeks to reflect driver behaviour). Obviously, this mix is
highly influenced by location and trip route, but many observers have commented on the fact that the
“typical” mix used, say, by the USEPA or by the EU to report average fuel consumption is probably
incorrect on average. The EU used to utilize a one-third each mix of urban, 90 km/hr highway and 120
km/hr highway fuel consumption values to derive a composite value, but a 1989 TRRL (UK) study3
showed a mix of 60% urban, 26% at 90 km/hr and 14% at 120 km/hr was significantly better in
matching “average” in-use consumption. The EU subsequently modified its test cycle, but the change
is not thought to have significantly reduced shortfall.

     Increased congestion levels in the suburbs and highways may lead to increasing fuel
consumption, since city cycle fuel consumption in typically 30 to 40% higher than consumption at
highway speeds. However, it is less of an issue for consumers since city and highway fuel economy
are separately provided in most OECD countries.

      Trip length is an important variable, especially from cold start conditions, for determining fuel
economy. Short trips generally result in higher fuel consumption due to the need to warm up the
engine to operating temperature. As noted, short trips at cold ambient temperature result in the greatest
fuel economy penalty. Even if average trip length is correctly represented in the test cycle, the non-
linear nature of the trip length effect will always result in on-road average fuel consumption being
worse than measured fuel consumption (i.e., the improvement in fuel economy for longer than average
trips does not compensate for the shortfall in shorter-than-average trips).

      Higher levels of congestion with more extended idling also occur in many OECD countries, as
the suburbs become as congested as the city-centre. Extended idling or “creeping” forward at very low
speeds causes a very large fuel consumption penalty, but there is little analysis or data to provide
estimates how much idling/creeping type driving has increased over the years for the entire vehicle
fleet.

Road Conditions/Topography

     The fuel economy certification test is conducted on a smooth tyre contact surface, and no
simulation of gradients is employed. In the real world, twisting roads, unpaved surfaces and
mountainous regions are also responsible for fuel economy reduction. In most countries, the effects of
twisting roads and unpaved surfaces are quite small, on average, because they are infrequently


                   TECHNOLOGY AND POLICIES TO IMPROVE VEHICLE IN-USE FUEL ECONOMY – ISBN 92-821-0343-9 - © ECMT, 2005
LITERATURE REVIEW OF “SHORTFALL”   - 25



encountered. Travel under these conditions is generally a small percentage of total travel, and the
effect of winding roads and unpaved surfaces typically increases overall consumption by 2 to 5%.
These conditions often act to reduce driving speed, which has a favourable effect on highway fuel
economy.

      Mountainous condition can be more common in some regions/countries and the effect on fuel
consumption depends on the gradients encountered. Moderate gradients (less than 4 to 5%) impose
very small penalties on fuel economy since much of the energy lost in climbing is recovered in the
downhill phase of driving. Steeper gradients, involving operation in a lower gear, can have large
effects since the climbing energy is also dissipated in braking downhill. Locations where steep grades
are encountered are quite limited in most OECD countries, and such areas are also less populated, so
that the average contribution to shortfall is typically limited.

Vehicle Accessories and Cargo

      Many vehicles are equipped with a number of power accessories such as a stereo systems, power
windows/seats, defrosters and air conditioning. Typically, most certification tests do not test vehicles
with any of the accessories turned on. The U.S. test procedures simulate air conditioner use by
utilizing a 10% increase in the setting of the power absorption unit on the dynamometer, and the test is
not sensitive to actual air-conditioner performance. Typically, the use of these power accessories
degrades fuel economy, but their effect can be seasonal. Defrosters and air conditioners can use
significant amounts of power, but other accessories are not important contributors to shortfalls.

     Of the accessory loads, only the air conditioner load is significant as a contributor to shortfall,
since other accessories such as the electric defroster are not typically turned on for long periods of
time. The air conditioner, when turned on, can decrease fuel economy by 10 to 20% depending outside
temperature and vehicle engine size. In some OECD countries such as the U.S. and Australia, air
conditioners may be used for six to eight months of the year.

     An issue peculiar to light trucks is that many pickup trucks carry cargo or tow boats/campers, but
the certification test does not reflect this fact. In fact, many OECD countries continue to test trucks at a
test weight equivalent to the curb weight + 300 lbs. (136 kg), while many trucks operate with a load
significantly more than just the driver and fuel load simulated on the cycle.

     Studies of actual on-road fuel economy in the U.S. (which has the greatest prevalence of light
trucks of all OECD countries) also show that light trucks have greater percentage difference in fuel
consumption between on-road and test value than cars (see Section 2.2.7). Part of this difference can
be attributable to greater use under loaded conditions.

Vehicle Technology-Specific Effects

     Since shortfall is a function of many variables including location, season and driver behaviour,
any assessment of average shortfall, and variations of shortfall by vehicle technology require large
samples of data from an unbiased pool of consumers across all seasons and locations. Such large scale
surveys were conducted by the U.S. DOE and EPA in the late 1970s and early 1980s and a 1982 SAE
Paper by McNutt, et al.5 summarized the results of several years of data analysis. Shortfall was



TECHNOLOGY AND POLICIES TO IMPROVE VEHICLE IN-USE FUEL ECONOMY – ISBN 92-821-0343-9 - © ECMT, 2005
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